From the plaque:
This route was used by Luiseño
and Gabrieleno Indians, whose villages were nearby. Leandro
Serrano established a home here in 1820. Jackson and Warner
traveled the road in 1831, and Frémont in 1848.
It was the southern emigrant road for gold seekers from
1849 to 1851, the Overland Mail route from 1858 to 1861,
and a military road between Los Angeles and San Diego
from 1861 to 1865.
Bronze plaque placed by the California State Park Commission in cooperation with the Woman's Improvement Club of Corona May 10, 1959 and replaced in 2013 with this granite plaque in cooperation with Glen Ivy Hot Springs.